The present invention relates to a modulated real time sound display apparatus. Specifically, a multi-channel sound display apparatus is provided which permits display of an audio signal spectrum in discreet frequency bands.
Sound display apparatus are known in the art which will visually display the frequency components contained within an audio signal. One such device is shown in U.S. Pat. No. 3,163,077 wherein a single input signal is divided to provide three signals having a different frequency spectrum. Such devices are known to provide a pleasant lighting effect which varies in response to the audio signal. Thus, in addition to listening to the audio signal, a visual impression is given which varies in accordance with the listened-to sound. It is desirable in light display apparatus to provide separation control whereby the individual lights activated in response to individual portions of the audio signal spectrum have a variable and selectable degree of separation between individual lights. For instance, a plurality of lights, each being responsive to a different frequency spectrum, can be controlled such that the lights appear to be distinctly operated independent from each other.
By using a preamplifier electrically disconnected from the remainder of the circuit and an amplifier for conveying an isolated audio signal to circuitry connected directly to the main power line an instantaneous sound level is obtained which is completely rectified and averaged.